Bent arms that cannot be straightened may be caused by osteoarthritis, elbow trauma and muscle strain, etc., which can be effectively improved through active treatment. 1. Osteoarthritis: If the patient has osteoarthritis, osteophytes and other diseases, it may cause the elbow joint to jam when it moves to a certain position. Treatment can be improved by arthroscopic cleaning or joint replacement surgery. 2. Elbow trauma: If the patient suffers from elbow fracture or ligament injury due to trauma, he/she may not be able to straighten his/her arm. It can be treated by plaster fixation or surgical repair. 3. Muscle strain: If the patient often carries heavy objects or engages in heavy physical activities, the elbow joint muscle strain may occur, thus the phenomenon of the arm bending and stretching is not straight. It can be treated by hot compress or massage. Therefore, it is recommended that patients go to the hospital in time for a detailed examination to clarify the cause of the disease and then target treatment.